1. Field of the Invention
The present invention relates to a spectroscope that performs spectrum resolution of a light beam to extract a separated light beam having an arbitrary wavelength, and a confocal scanning microscope providing this spectroscope.
Priority is claimed on Japanese Unexamined Patent Application, First Publication No. 2003-026043, the content of which is incorporated herein by reference.
2. Description of Related Art
Conventionally, a confocal scanning microscope is known in which an observation object is excited by illuminating it using a laser beam, and at the same time, allows fluorescence observation by displaying the fluorescent light from this observation object as an image (for example, refer to Japanese Unexamined Patent Application, First Publication No. Hei 8-43739).
In a confocal scanning microscope, a spectroscope that extracts a separated light beam having a particular wavelength from this fluorescent light is provided for observation, and in terms of increasing the precision of the resolution, avoiding the capture of side lobes of the separated light beams having other wavelengths and the like in the separated light beam to be extracted is desirable.
In order to solve this problem, a structure is used in which the shape of the small aperture that focuses the light beam (fluorescent light) before spectrum resolution is square (refer, for example, to Japanese Unexamined Patent Application, First Publication No. 2002-502050). This will be explained using FIG. 12.
As shown in the figure, the light beam 1 from the observation object (not illustrated) first passes through the small aperture 2 in which the polygonal passage hole 2a is formed, and then is incident on the prism 4 after passing through the focusing optical system 3. Thereby, this light beam 1 is resolved into the separated light beams 5 of various wavelengths. The resolved separated light beams 5 pass through another focusing optical system 6 to build up images on the dispersion plane 7. In this manner, in the image formed on the dispersion plane 7, side lobes are arranged in an X shape centered on the spot 8a having the highest optical intensity, and arrayed in the spectrum direction (in the figure, only two are illustrated for the explanation). Thereby, it becomes possible to extract the desired separated light beams by blocking from among these images those whose separated light beams do not have the necessary wavelength in the spectrum direction.